In the world of living creatures, simple-minded animals often cooperate
to achieve common goals with amazing performance. One can
consider this idea in the context of robotics, and suggest models for
programming goal-oriented behavior into the members of a group of
simple robots lacking global supervision. This can be done by controlling
the local interactions between the robot agents, to have them
jointly carry out a given mission. As a test case we analyze the problem
of many simple robots cooperating to clean the dirty floor of a
non-convex region in Z2, using the dirt on the floor as the main means
of inter-robot communication.